The invention concerns a catheter for intravascular application, with a proximal and a distal end and a catheter longitudinal axis, comprising a shaft extending along the catheter longitudinal axis from the proximal end to the distal end and having a fluid-tight shaft wall and at least one lumen which is adapted to guide a fluid, which extends from the proximal end at least into the proximity of the distal end of the catheter, and which is enclosed by the shaft. The catheter also has at least one electrically conductive wire which extends from the proximal end at least into the proximity of the distal end of the catheter along the catheter longitudinal axis.
The state of the art discloses catheters which include wires in the form of control wires for deflecting the distal end of a catheter, or electrical feed lines for electrodes, for example high-frequency lines in the case of ablation catheters or also in the form of electrical feed lines for sensors. The wires, in the form of control wires or electrical feed lines, are usually guided in the interior of a catheter shaft.
Those catheters which are known from the state of the art involve the problem that the wires which extend in the catheter shaft, when using the catheter during a magnetic resonance tomography, are significantly heated by high, electromagnetically-induced currents, so that the conduction of heat results in a rise in the temperature of the catheter shaft, which entails the risk of coagulation along the catheter shaft.
In the case of ablation catheters, there is equally the risk of coagulation phenomena along the catheter shaft disposed in the body, due to high, high-frequency currents which are passed in the feed lines to the ablation electrode and which result in an increase in the temperature of the feed lines and, by way of heat conduction, an increase in the temperature of the catheter shaft.
DE 693 32 414 T2 discloses a cryogenic catheter which has lumens for guiding a coolant and temperature sensors at the distal end for monitoring the temperature of an ablation electrode and the coolant.
U.S. No 2003/0004506 and U.S. Pat. No. 5,348,554 disclose catheters having a fluid-cooled ablation electrode.
U.S. Pat. No. 5,980,515 discloses a catheter with a rotating saw tool and a flushing device, wherein the flushing device can also serve for cooling an ablation electrode.
The problem of catheter shaft heating due to electrically conductive wires extending in the shaft is not referred to in those patent specifications and is also not resolved.